Japan's Space Agency Applied Lessons Learned to Land Jumping Robots on an Asteroid
IMAGE COURTESY OF THE JAPAN AEROSPACE EXPLORATION AGENCY
Rendering of Rover-1A, back, and Rover-1B, foreground, as they explore the surface of the asteroid
One small misstep for a project has led to one giant leap forward for space exploration. The Japan Aerospace Exploration Agency (JAXA) made history when it landed two roving robots on a moving asteroid in September. It was the first time mobile robots landed on an asteroid. The robots will jump around, sometimes going as high as 15 meters (49 feet) into the air and staying above the surface for as long as 15 minutes to survey the asteroid's features. The robots are part of a larger JPY30 billion project to survey and gather data on the asteroid, with the hope that the information will reveal more insight into the origins of the solar system.
To execute the robot phase, JAXA drew on lessons learned from a similar but failed effort that was launched in 2003. On that portion of the multiyear project, dubbed Hayabusa, the robots successfully released from a spacecraft but drifted into space instead of landing on the asteroid.
Before any design work began on the new project, the Hayabusa2, the team reviewed granular project details—looking at everything from technical aspects to project management methodology. The captured lessons learned numbered well into the hundreds, says Yuichi Tsuda, PhD, project manager, Hayabusa2, JAXA, Chōfu, Japan. “I would say Hayabusa was the most ambitious Japanese space mission in history.”
Yet that ambition created a major weakness. Since every aspect of the Hayabusa project was groundbreaking for the agency, each project member was an expert in a specific field. Each member's role was so specialized that no one else could do it, with the siloed nature making off-the-cuff collaboration difficult.
For Hayabusa2, JAXA created a project team that included multiple people who were able to take care of each piece of specialized technology. “Communication between many good experts is the best way for sharpening such technologies and increasing reliability,” says Dr. Tsuda. The organization's structure was also amended to allow for more efficient communication. “We made a very flat organization, so that members can communicate with each other as easily as possible,” he says.
—Yuichi Tsuda, PhD, Hayabusa2, JAXA, Chōfu, Japan
The project team also took an agile approach to quickly iterate while developing technology. “The team recognized that the most critical aspect of the Hayabusa2 project was quick response,” he says. That was particularly useful when the team was developing technology for when the robots got close to the asteroid, he says. To test and iterate during development, the project team built a high-fidelity spacecraft simulator to practice the descent toward the asteroid surface. The team also practiced the deployment of the rovers so they would land in precisely the right spot on the asteroid. “In this way, the members could experience 'failure' before they fly, and many people could polish their skills to become experts,” Dr. Tsuda says.
The team adjusted the original project schedule to include time for the new probe to perform a dedicated descent to release the rovers. The adjustment helped ensure that the team had maximum control over the descent trajectory and separation sequence. The robots were then released at a lower altitude in the hope that it would increase the odds of a successful touchdown.
The commitment to lessons learned paid off—both rovers landed in good condition on the asteroid. They're now transmitting images as they explore the asteroid's surface. The larger mission aims to return asteroid samples back to Japan by 2020. “Knowing about an asteroid itself broadens our understanding on the solar system and life,” Dr. Tsuda says. Additionally, developing the technology to return to Earth is important for future human space activity, he says. “The success of Hayabusa2 will accelerate our will to [use this] technology for other planets in the solar system.” —Ashley Bishel